1. Field of the Invention
The present invention generally relates to saw guides for wood sawing which include lubricating and cooling capabilities.
2. Description of Prior Art
Multiple blade saw systems are widely used throughout the lumber industry. Most multiple blade saw systems use very thin circular saw blades. Thin saw blades use less power and provide higher yield. However, thin saw blades require saw guide systems to stabilize the blades during cutting and prevent buckling. Typically this is done by sandwiching each blade between two flat lubricated surfaces which act as bearings supporting the blade. These bearing surfaces usually consist of a low friction material supported by a metal block adjacent the cutting zone. Many existing guiding systems use babbitt saw guides which provide a soft bearing surface that wears in. Other systems use bearing surfaces made of hard materials which are wear resistant.
Saw guide systems normally include a means of lubricating and cooling both the saw guides and saw blades. Typically the liquid lubricants are carried into the narrow space between saw guide and saw blade in the form of a mist created by forcing high pressure air through a venturi nozzle or the like. Other systems apply liquid lubricants and coolants directly into the space. Some systems are provided with dual sets of passages in each saw guide to provide both air oil and air water mists.
Normally all water and oil provided for lubrication and cooling to the saw guides is lost into the sawing environment, soaking into the sawdust, onto the lumber products, or draining away. In order to conserve water and oil sequencing systems are utilized which vary the application rates of the water and oil so as to provide the minimum required during the sawing process.
Additional cooling is sometimes provided by water deluge systems which spray water onto the saw blades and guides.
A problem with saw guide systems in general is the wear of bearing surfaces. Guides require frequent changing. Typically babbitt shifting saw guides last only a hundred hours.
It would be desireable to have a guide system which is very effective in holding the blade in the center position between the bearing surfaces. This would reduce bearing wear and extend the useful lives of the saw guides, thus reducing cost associated with frequent changes. An effective guide system also allows the use of thinner kerf saw blades which increases yield directly.
A problem with saw systems in general is the heating of saw blade and adjacent bearing surfaces. The heating causes dimensional instabilities which contribute to wear. It would be very desireable to increase cooling of the bearing surfaces and saw blades. This could substantially reduce wear and extend the useful lives of the saw guides, thus reducing cost associated with frequent changes. Sufficiently increased cooling would also eliminate the need for using deluge systems.
It is also desireable to recover and recycle liquid coolants. This is advantageous for limiting discharge into the environment. For example, a recirculating cooling system would be very desireable. It could allow greater application of coolants to the guide bearing surfaces without increasing coolant loss into the environment. Such a closed loop cooling system could greatly reduce water use.